The protective effects of captopril and nitric oxide on solitary kidney after chronic partial ureteric obstruction

To determine whether vasodilator agents (captopril and nitric oxide) change the morphological and functional effects of chronic partial ureteric obstruction in solitary kidney tissue in unilaterally nephrectomized rats.

Each of 50 prepubertal Wistar albino rats underwent right nephrectomy and were then assigned to one of five groups. Rats in group 1 underwent a sham operation (control) and in the other groups the ureter of the remaining kidney was partially obstructed by surgery. In group 2, no drug treatments were given; in groups 3, 4 and 5 captopril, L-arginine methyl ester (L-Arg) or NG- nitro-L-arginine-methyl ester, respectively, were given for 3 weeks. In all rats, diuretic scintigraphy was used to measure kidney perfusion, glomerular filtration rate (GFR) and concentration. Blood urea nitrogen (BUN), serum creatinine levels, kidney parenchymal weight and pelvic volume were measured and the kidneys evaluated histopathologically.

Renal perfusion was significantly greater in both group 3 and 4 than in group 2. The GFR was 18% greater in group 3 and 22.3% greater in group 4 than in group 2. The GFR was decreased by 67% in group 5 compared with the control group. The mean parenchymal weight, mean pelvic volume, BUN and serum creatinine in the four groups with a partially obstructed ureter were significantly different from the control group. There also were significant differences between group 2 and groups 3--5, and between group 2 and group 3. Histological damage was severe in all four groups with partial ureteric obstruction, but in the drug-treated groups, medullary fibrosis was less frequent.

After 3 weeks of treatment, captopril and L-Arg both improved kidney perfusion, GFR, BUN and serum creatinine levels, but were less effective in preventing parenchymal atrophy and changes in pelvic volume.